AISI 304/304L DIN 1.4301/1.4306-1.4307

DEFINITION:

304 quality stainless steel is the type of stainless steel that is the most frequently used and versatile steel in the world. It has excellent treatability and welding capabilities. The austenitic grade 304 allows severe deep drawing without intermediate annealing, therefore it is the dominant grade in production that requires deep drawing such as kitchen sinks, natural gas chimneys and saucepans with handles. It has multi-purpose utilization in sectors such as industry, architecture and transportation.

304L is a type of 304 with lower carbon. Nickel(Ni) ratio is a little higher compared to 304 (please see the alloy chart). Austenitic grade allows excellent toughness to such grade and preserves its toughness at even cyrogenic temperatures. It is partially harder to process and harder to process 304L compared to 304.

CHEMICAL COMPOSITION:

Grade

C

Mn

Si

P

S

Cr

Mo

Ni

N

304

min.

max.

-

0.08

-

2.0

-

0.75

-

0.045

-

0.030

18.0

20.0

-

8.0

10.5

-

0.10

304L

min.

max.

-

0.030

-

2.0

-

0.75

-

0.045

-

0.030

18.0

20.0

-

8.0

12.0

-

0.10

CORROSION RESISTANCE:

304 AND 304L have excellent corrosive resistance in normal atmospheric environments. Subject to internal material pitting and crevice corrosion in warm acidic environments and to stress corrosion cracking above 60C'nin .

Considered resistant to potable water with about 200 mg/L chlorides at ambient temperatures, reducing about to 150mg/L at 60C.

HEAT RESISTANCE:

304 has good oxidation resistance in intermittent service to 870C and in continuous service to 925C. However, it will have reduced aqueous corrosion resistance in the temperature range of 425-860C. Grade 304L is more resistant to carbide precipitation since it has lower carbon (C) percentages.

HEAT TREATMENT (ANNEALING):

Heat to 1010 1120C and cool rapidly. Since low on carbon (C), these grades cannot be hardened with further thermal treatment.

WELDING:

Excellent weldability by all standard methods such as; electrode, gas, rod welding, etc.. Welding of 304 is pre-qualified with Grade 308 and 304L with Grade 308L rods or electrodes. Heavy welded sections in Grade 304 require post-weld annealing, but this is not required in lighter welded sections. Grade 304L does not require that even for heavy welded sections (e.g. for 6mm and over).

MECHANICAL PROPERTIES:

Grade

Tensile Strength (MPa) min

Yield Strength 0.2% Proof (MPa) min

Elongation (% in 50 mm) min

Hardness

Rockwell B (HR B) max

Brinell (HB) max

304

515

205

40

92

201

304L

485

170

40

92

201

PHYSICAL PROPERTIES:

Grade

Density (kg/m3)

Elastic Modulus (GPa)

Mean coefficient of thermal expansion (mm/m/C)

Thermal Conductivity (W/m.K)

Specific Heat 0-100C (J/kg.K)

Electric resistivity (nW.m)

0-100C

0-315C

0-538C

at 100C

at 500C

304/L

8000

193

17.2

17.8

18.4

16.2

21.5

500

720

OTHER COUNTRY NORMS:

Grade

UNS No

British Norm

Euronorm

Swedish SS

Japanese JIS

BS

En

No

Name

304

S30400

304S31

58E

1.4301

X5CrNi18-10

2332

SUS 304

304L

S30403

304S11

-

1.4306

X2CrNi19-11

2352

SUS 304L

APPLICATIONS:

IN STOCKS:

Bar, hexagon, strip, square, angle, sheet, pipe, fittings.